Bacterial infections and viral infections have different symptoms and indicators. It is recommended to determine whether bacterial infections or viral infections are present under the guidance of a doctor and to carry out targeted treatment. 1. Bacterial infection: patients with bacterial infection will show an increase in the total number of white blood cells and neutrophils, in addition to an increase in calcitoninogen and a moderate or significant increase in C-reactive protein after bacterial infection. 2. Viral infections: Most patients with viral infections will show normal blood count and C-reactive protein, in addition to normal or decreased total white blood cell count and increased total lymphocyte count. It is worth noting that if the use of antibacterial drugs is ineffective, the possibility of bacterial infections cannot be completely excluded, such as insensitivity to the selected drugs or infection with drug-resistant strains of bacteria may lead to the ineffectiveness of antibacterial drug treatment. Therefore, in general, changes in the number of white blood cells, granulocytes and lymphocytes can be used to determine whether the infection is bacterial or viral, and it is recommended to confirm the diagnosis and treatment under the guidance of a doctor.